In the manufacture of paper, a stock is deposited onto the moving wire on the Fourdrinier table of a paper machine. The stock which consists of water, fiber, fillers and chemicals; typically the stock contains over 95% water. Deckle boards are needed to prevent the stock from flowing off of the fourdrinier machine. They act as dams, stopping the cross-direction (“CD”) flow of the stock. Historically all the designs of paper machine deckles are inactive or static relative to having a function as an active drainage element. They redirect the CD flow of the stock but do not actively drain water from the stock. A byproduct of this damming action is that they create what are known as deckle waves. Deckle waves contribute to non-uniform moisture and basis weight profiles which in-turn contribute to non-uniform caliper profiles. All these sources of non-uniformity can cause rejection of paper or paperboard produced on a fourdrinier type paper machine, resulting in increased costs and production losses.
The present invention solves the problem of creation of non-uniform profiles caused by deckle waves by transforming the deckle boards into active drainage elements in the paper forming area of the paper machine. This addresses the root cause of problem at the point it is created, rather than treating the symptoms further down the paper machine with such things as CD profile equipment, and it solves the problem without the need for expensive rebuilds such as dilution control head boxes.